The invention concerns a refractory nozzle for arrangement in or on a wall of a metallurgical crucible, particularly for steel melts, having a flow passage and a discharge duct surrounding the flow passage, wherein the discharge duct has a surface delimiting the flow passage and an external housing. Such devices are needed in the casting industry in order to make it possible for metal melts, particularly steel melts, to run out of melt crucibles.
An arrangement of this type is known, for example, from British patent specification GB 2 157 210 A. Here, a so-called immersion nozzle is described, from which molten steel flows from an upper crucible into a lower melt crucible, wherein the nozzle or spout dips into the melt of the lower crucible. This device contains a gas feed, through which the optional gases can be introduced into the metal flow. This can be desirable under certain circumstances, but in many cases it is disadvantageous, namely when properties of the melt are thereby influenced in an unfavorable and undesired manner. The regulation of the flow takes place with such nozzles, either by so-called stopper rods which are lowered from above into the upper opening of the device and close the opening or leave it wholly or partially open, or by slides which are pushed laterally and perpendicular to the flow direction across the cross section of the nozzle and thereby close it. Such a control process is relatively inexact and mechanically expensive. Moreover, as a rule, it leads to the formation of turbulence within the metal flow, whereby an adhesion of the through-flowing metal takes place on the wall of the nozzle.
Similar nozzles are described in Japanese published patent application (kokai) JP 61-42899 or European patent no. EP 379 647 B1.